TiN has been widely used as hard layer on cutting tools. However, due to its relatively poor oxidation resistance at elevated temperatures, the focus has shifted towards more complex ternary and quaternary compounds, e.g. Ti—Al—N, Ti—Al—Si—N and Ti—Cr—Al—N with improved high temperature performance. For example, Ti—Al—Si—N has been reported as super hard, H>40 GPa, explained in terms of a two phase structure consisting of crystalline phase of NaCl-type in combination with x-ray amorphous Si3N4 or SiINx.
EP 0588350 discloses a hard layer of Ti—Si—N composite material deposited on a body using an evaporation technique resulting in layers with a composition of TiaSib where a is between 75 at % and 85 at % and b is between 15 at % and 25 at %.
JP 2004-338058 discloses a hard coating comprising a compound nitride layer of Ti, Si and Y. The layer has a layered structure composed of gradient layers wherein each layer has a maximum Si content and a minimum Si content. JP 2004-338008 and JP 2004-322279 disclose similar hard coatings comprising a compound (Ti,Si,Cr)N layer and (Ti, Si, Zr)N, respectively.
CN 101338411 discloses Zr—Si—N layers grown by co-sputtering of pure Zr and pure Si targets in a mixed argon and nitrogen discharge on substrates to a total thickness of 2 to 3 μm.
EP 1736565 discloses a cutting tool insert, solid end mill, or drill, comprising a body and a coating composed of one or more layers of refractory compounds of which at least one layer comprises a cubic (Me,Si)X phase, where Me is one or more of the elements Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and Al, and X is one or more of the elements N, C, O or B.
WO2005100635A1 discloses an AlxSiyMezN coating, 0.001≦z≦0.08 where Me is a metal dopant element, for example Zr.
Today industry continuously seeks solutions for economic and high productivity/feed-through manufacturing. To meet these demands there is a need for new materials with advanced properties to improve tool life during operation. Within the metal cutting tool industry, a major part of this effort is focused to improve the wear behavior of the cutting tools by designing the properties of the coating material used in the application. Typically, a high productivity/feed-through cutting process results in a dramatic increase of the tool temperature and hence a coating material with a high temperature wear resistance is essential.